i put a half slab in a hole (1 deep) and cobweb over it. they get stuck. i go into a narrow passage with a skeleton following me also, watch the creeper get pissed at the skeleton, and blow them both to hell. i put a pressure plate leading to 4 tnt each 4 blocks away and give the creeper a taste of its own medicine.
Have a skeleton hit a creeper. Then try to push him into a minecart before he can get close enough to the skeleton. Press a button, and he'll take off on a nice roller coaster ride, ending with a dip in a lava lake.
Dispensers with random splash potions.
Disguise as a creeper and tell him to blow up your neighbor's house.
Plant a sapling and then use bone meal on it as the creeper passes over it.
Lure it into a cave with a sand ceiling. Then trigger a cave in.
Frantically flail with whatever you happen to be holding when you hear the hissing sound or notice the creeper standing next to you, then travel all the way back to the crater to see how much of your stuff remained intact.