Achievables #3: The Oregon Trail

Get Out and Push
5 - Attempt to leave Independence, Missouri with no oxen.

Traveling in the Nude
5 - Leave Independence, Missouri with no sets of clothing.

Ride Along, Fagballs
10 - Give one of your party members a name that would be blocked by the XBox Live censors.

Died of Dysentery
10 - Have a party member die from every possible disease.

Tragedy Strikes
10 - Have a party member die from every possible non-disease disaster.

And We'll All Float On All Right
5 - Caulk your wagon and float it across a river.

Quick Shot
35 - Kill 100 rabbits, squirrels, or beavers while hunting.

What A Waste
10 - Leave behind 10,000 pounds of food while hunting.

No Rush
25 - Rest for over 100 days in a single journey.

Oh, Right, Learning History
10 - Read the blurbs about each location.

So Close
10 - Your last party member has drowned in the Columbia River.

Welcome to Willamette
10 - Complete a journey on the Oregon Trail.

Jack of all Trades
25 - Complete a journey as each job class.

Mass Migration
30 - Complete journeys with 500 total surviving party members.

Total: 200

BLEEP BLOOP.

Achievables #2: Ms. Pac-Man

Yes, there already exist achievements for the XBLA release of Ms. Pac-Man. In my opinion, they're not particularly creative.

Out of 200, 90 is for eating one of each fruit. A further 25 is for eating all 4 ghosts off a single power pellet, and 30 more for doing it 4 times in a stage. 65 rests on the ability to reach level 22. These achievements are only slightly different from those they gave to original Pac-Man. Furthermore, they violate a key rule which I've just made up:

At least one achievement name must attempt to be funny or clever.

So if I could do this whole thing over, here's what I've got:

Wakka
1 - Eat one dot.

Wakka Wakka
10 - Eat 1000 dots.

Wakka Wakka Wakka
25 - Eat 25,000 dots.

Wakka Wakka Wakka Wakka
50 - Eat half a million dots.

Power Up!
4 - Eat a power pellet.

Wakka Wakka Fruit
10 - Eat a fruit.

Girl's Gotta Watch Her Figure
40 - Eat one of each type of fruit.

Wait, That's Not A Fruit
20 - Eat a pretzel.

Pills Here!
30 - Consume all 4 power pellets on a level without consuming any ghosts.

I Ain't Afraid Of No Ghost!
10 - Consume all 4 ghosts in a single power pellet.

Total: 200

BLEEP BLOOP.

Achievables #1: Commander Keen

Seeing as how Steam has already released Episodes 1-5 of Commander Keen as a single pack, I'll treat Keen as a full 1000-gamerscore release. Oh, and because it's awesome, I'm including Episode 6: Aliens Ate My Babysitter as well.

from Episode 1: Marooned on Mars:

Boing
5 - Acquire the Pogo Stick.

You're In Control
25 - Recover the Joystick.

Charged Up
25 - Recover the Battery.

This Sucks
25 - Recover the Vacuum Cleaner.

Clean-Burning Fuel
25 - Recover the Everclear.

Voices in my Head
10 - Listen to all the Yorp Statues.

Dark Side of Mars
10 - Teleport to the dark side of Mars.

Martian Surprise
25 - Discover the Secret City on Mars.

from Episode 2: The Earth Explodes:

Who Turned Out The Lights
5 - Use a lightswitch aboard the Vorticon Mothership.

Respect your Elders
10 - Listen to the two Elder Vorticons in stasis.

London is Safe
15 - Disable the Tantalus Ray aimed at London.

Paris is Safe
15 - Disable the Tantalus Ray aimed at Paris.

Rome is Safe
15 - Disable the Tantalus Ray aimed at Rome.

Cairo is Safe
15 - Disable the Tantalus Ray aimed at Cairo.

New York is Safe
15 - Disable the Tantalus Ray aimed at New York.

D.C. is Safe
15 - Disable the Tantalus Ray aimed at D.C.

Sydney is Safe
15 - Disable the Tantalus Ray aimed at Sydney.

Moscow is Safe
15 - Disable the Tantalus Ray aimed at Moscow.

from Episode 3: Keen Must Die!:

I Am So Lost
10 - Use the teleporters on Vorticon VI 50 times.

It's not a Myth
25 - Ride the Lock Mess Monster to the secret level.

I Am Invincible
15 - Pick up an ankh.

Filicide
10 - A vorticon mother aimed a fireball at you and hit one of her own children.

The Big V
50 - Acquire the highest honor the Vorticon race has to offer.

from Episode 4: Secrets of the Oracle:

One Council Member
10 - Rescue one council member.

Quorum
25 - Rescue four council members.

This Meeting Will Come to Order
40 - Rescue all eight council members.

I CAN swim!
15 - Find the Wetsuit.

Swim Swim Hungry
5 - Narrowly avoid being eaten by the second-dumbest creature in the universe.

They'll Be Afoot
25 - Discover the Pyramid of the Forbidden.

Number Nine?!?
40 - Rescue the council's janitor.

from Episode 5: The Armageddon Machine:

Lower Level Breached
20 - Reach the Security level of the Omegamatic.

Upper Level Breached
30 - Disable all four devices guarding the upper level of the Omegamatic.

QEDestroyed
50 - Destroy the Quantum Explosion Dynamo.

The Planet Below
25 - Discover the secret base on Korath III.

Long Way Down
25 - Collect all the vials of Vitalin on Korath III in one jump.

from Episode 6: Aliens Ate My Babysitter!:

Beneath the Bean-With-Bacon
5 - Discover the secret tunnel beneath Keen's ship.

Cliffhanger
10 - Cross the cliff on Fribbulus Xax.

Om Nom Nom Nom
15 - Collect the second biggest sandwich Keen's ever seen.

Rocket Man
30 - Take the rocket to the Bloog Space Fortress.

Don't Tell Mom The Babysitter's Alive
45 - Rescue Molly.

To The Stars!
25 - Catch a ride to the Blooglab Space Station.

from no game in particular:

Now I Know My ABCs
25 - Learn the Galactic Standard Alphabet.

The Cake is Not a Lie
20 - Collect 100,000 points from cakes and pastries.

Brain Freeze
20 - Collect 100,000 points from frozen treats.

Sugar Rush
20 - Collect 200,000 points from sugary snacks.

Fast Food
20 - Collect 100,000 points from pizza and burgers.

Burp!
20 - Collect 150,000 points from sodas.

Achievement Unlocked
10 - Open 50 doors with keycards or gems.

The Enemy is Toast!
10 - Fire off 1000 shots.

The Many Secret Lives of Billy Blaze
10 - Collect 2000 total lifewater drops, Vitalin vials, and/or vivas.

Points After Death
10 - Collect an item after you die.

Total: 1000

BLEEP BLOOP.