BobPitch.com

Click any two animals next to each other (horizontally or vertically) and they swap round.
If that gives three identical animals in a row they vanish, if not they swap back.
Your time continuously ticks down, making animals vanish gives you more time.

If you're still bored after played Zookeeper, why not drop by and say hello at http://www.bobpitch.com

I didn't write zookeeper - if you like it there's a gameboy advance version called "Zooo" you might want to buy
Or now you can get it for your Nintendo DS for less than 15
Popcap Games