Reactive targets are the way to go with .22s, but only if the range you will be using allows them.
Most places frown on steel targets, due to the risk of ricochets.
If you're lucky enough to be able to use them, check out the Birchwood Casey line of steel reactive targets.
Very inexpensive and durable.
If you can't use steel, charcoal briquettes work good.
As does AlkaSeltzer tablets and the like.
Wine bottle corks, balloons, little toy soldiers, 'etc.
Let your imagine run wild.
If you're really unlucky, and the range will only allow paper targets, download pictures of small critters, from places like google images, and print them out.
Lots more fun than bullseye targets.