A mountain-man friend of ours gave us this one:
Fill a 5 gal plastic bucket about half full of water, make a 2x4 ramp up to the rim so the munks can get into it, then set it where they hang out. They fall in trying to reach the water, can't climb out, so they drown. So simple & it really works!--especially if you live in a dry area. Check the buckets daily, fish out the dead ones, then rinse and refill the buckets--this is important.

Yeah, it may sound cruel, but these little guys are terribly destructive, impossible to live-trap because they're too smart, and they won't eat rodent bait. After several thousand dollars in damage repair, they didn't look so cute anymore.

Chipmunks ripped out the insulation in our garage, tore up everything chewable, ate thru a bunch of wiring on the truck (a major repair bill). We ripped out the ruined garage insulation and stapled in heavy-duty 1/4" wire mesh 4 ft high around the perimeter. Then re-insulated and put in new drywall--another big expense. This, along with the water buckets has made big dent in the population.