Learn or try stuff

Solve 100 crossword puzzles
Make a 100 song mixtape CD
Make 100 pizza toppings
Play 100 guitar tunes
Tell 100 jokes
Inflate 100 balloons (by blowing)
Do 100 Okocha flicks
Do 100 keepie Uppies
Make 100 penalty saves (soccer)
Shoot 100 hoops (basketball)
Do 100 cartwheels
Learn 100 words of another language
Plant 100 trees
Solve a Rubics cube in under 100 seconds
Learn 100 capital cities
Make 100 pancakes
Make something with 100 pieces of LEGO
Do 100 sketch drawings
Do 100 headstands
Stay awake for 100 hours
Read 100 poems
Do 100 back-flips
Make 100 cakes
Stand on one leg for 100 minutes
Do 100 starboard tricks
Hold my breath underwater for 100 seconds
Throw 100 with 3 darts
Make an opening brea kof 100 (or more) at snooker
Wave at 100 strangers
Walk on my hands for 100 metres