If you aren't afraid of the chipmunks feelings: [ame=http://www.youtube.com/watch?v=MsuL4-g52tY]Chipmunk swimming pool of death (aka Chipper Dipper) - YouTube[/ame] Skip to 4:24 to see the trap.
If you are a bit compassionate, I've found the same method works, only with a large barrel, something like a 40 gallon trash barrel, but a bit smaller, about 36" tall. If you set up a 2X4 leading to the barrel, at a very gradual slope and bait the bottom of the barrel, they will end up in the bottom and not be able to get out. Then you haul them away. You have to go at least 10 miles to be sure the bastards won't come back. I've tried the small animal traps, but they seem to be able to squeeze through the doors. I've caught 3 with this method. They are very curious creatures, so you can use that to your advantage. I used apples and peanut butter to bait my trap. Good luck!