The Last Stand 2

http://www.maxgames.com/play/last-stand-2.html

This is the successor to the thrilling survival flash game "The Last Stand"! Some things have changed, like for example you can select where to search during the day. You can set up traps as well, and shoot at them during the zombie attack at night. Plus, now you can even equip your survivors with weapons.
Sadly there is not sky visible like in the first game, that will show the dawn of a new day. Still, very entertaining and this time you have to last 40 full days!

Age Of War

http://www.maxgames.com/play/age-of-war.html

An entertaining tactical war game where your units evolve from the stone age to the space age. Easy to learn and master, but the end can be a bit tiresome until you have the right tactic to get through to the enemy base and damage it ;)

Xeno Tactic 2

http://www.onlinegamesector.com/hra.aspx?game=3174

Wow, finally a successor to one of my all time favourite flash games: Xeno Tactic!
And by the way, there's a hack video on u tub for part 1: http://www.youtube.com/watch?v=JR0QGN0TFDw
(be warned, pretty strange visuals and audio ahead...)

There's also an expert time lapse video for part 2: http://www.youtube.com/watch?v=8JNkxQqmueI

Dolphin Olympics 2

http://www.kongregate.com/games/arawkins/dolphin-olympics-2

Tony Hawk meets Endless Ocean. You're playing as a Dolphin trying to do some trick jumps and dives to score maximum points and combos. It's a funny little game, especially if you're one of those compulsive Achievement Hoarders or Highscore Breakers.

(via Toa)

Hell of Sand

http://andyslife.org/games/sand.php

Hell of Sand is more a Toy than a Game but it still is an entertaining little java (yeah, it's not flash all right) piece. There are a number of faucets and tools that you can play with to create flows of sand, salt or water. With some more mechanics and possibly limited use of the tools this could be a nice puzzle game. Also playing around with the C4 is a lot of fun.

(via Kotaku)

You Have To Burn The Rope

http://mazapan.se/games/BurnTheRope.php

If you're frustrated by increasingly complex and difficult videogames, maybe it is some time for you to play some Burn the Rope. A small, satirical / subversive Spiel that should sneak a smile to your face. (found via this Gamasutra Article on subversive games)

Check out the other flashgames on the site for more little experiments.

Eyemaze Growcube

http://www.eyezmaze.com/grow/cube/

Grow Cube, a small puzzle game where you have to add objects to a cube in the right order. You might have already seen this game or a similar one but it still is something to mention. The animations and graphics are lighthearted and fun but the gameplay requires a lot of trial and error and can be quite frustrating. Nevertheless it is worth a look but I recommend you turn off the music - it can get annoying quickly.