6 week 100 pushup challenge.

I do!!! how does that work?

I found something online about 12 week crunch challenge i guess you can just double everything so it'd be 6 weeks.
Week 1 Challenge: Complete 20 basic crunches each day. Can’t do 20 at a time? Break it up into two sets of 10 or four sets of 5.

For the basic crunch:
Lie on your back, with knees bent and feet flat on the floor.
Beginners: cross arms over chest; others: rest hands behind the head (be sure NOT to pull on your neck). In either arm position, place your chin at a fist's distance from your chest.
Raise your chest and shoulders several inches from the ground, keeping your feet and lower back flat on the floor. Exhale as you come up; inhale as you lower back down.
Keep your movements slow and controlled, feeling the contraction in your midsection only. Fast jerky movements do not work the muscle properly.
When doing a crunch remember to pick a spot on the ceiling and keep your eyes focused on it to avoid pulling on your neck, and do not bring your elbows in or forward. Another option if you can’t stop pulling on your neck is to cross your arms across your chest. Take a deep breath, then exhale while curling up and forward until your shoulder blades are lifted off the floor. Hold for a moment at the top of the movement, fully exhale all of the air in your lungs for complete contraction of the abs, then slowly lower yourself back to the floor.

100 pushups challenge:
http://hundredpushups.com
week 1

So, you've completed your initial test and you're keen to start the program? Great!

If you managed 5 or less push ups in the test, follow column 1.
If you completed between 6 and 10 push ups, column 2 is for you.
Between 11 and 20 consecutive push ups? Impressive! Column 3 is what you're looking for.
More than 20 push ups? I would suggest starting the program on Week 3. Choose either Column 2 or 3 based on the number of push ups you managed in your initial test.
For example: let's say you managed 8 push ups. Looking at the second column, Day 1 begins with Set 1 (6 push ups), a rest period of 60 seconds, before moving on to Set 2 (6 push ups). Rest for 60 seconds and continue with Set 3 (4 push ups) and Set 4 (4 push ups), before finishing with Set 5 and as many consecutive push ups as you can comfortably manage (at least 5, but not so many that you damage muscle tissue). The 60 seconds rest between each level should allow you to complete the workout, but I promise it will get tough towards the end.

Treat yourself to a rest day before moving on to Day 2, and then again before you complete Day 3. I find that Monday, Wednesday, Friday works well and allows you to use the weekend for rest and recovery before moving on to the next stage of the program. Feel free to juggle the plan around to meet your busy schedule, but make sure you rest in between workout days.

week 1: pick the appropriate column depending on your initial test results
DAY 1
REST 60 SECONDS BETWEEN EACH SET (LONGER IF REQUIRED)
up to 5 push ups 6 - 10 push ups 11 - 20 push ups
SET 1 2 6 10
SET 2 3 6 12
SET 3 2 4 7
SET 4 2 4 7
SET 5 max (at least 3) max (at least 5) max (at least 9)
COMPLETED THIS WORKOUT? GO LOG IT AT PUSH UPS LOGGER!
DAY 2
REST 90 SECONDS BETWEEN EACH SET (LONGER IF REQUIRED)
SET 1 3 6 10
SET 2 4 8 12
SET 3 2 6 8
SET 4 3 6 8
SET 5 max (at least 4) max (at least 7) max (at least 12)
COMPLETED THIS WORKOUT? GO LOG IT AT PUSH UPS LOGGER!
DAY 3
REST 120 SECONDS BETWEEN EACH SET (LONGER IF REQUIRED)
SET 1 4 8 11
SET 2 5 10 15
SET 3 4 7 9
SET 4 4 7 9
SET 5 max (at least 5) max (at least 10) max (at least 13)
COMPLETED THIS WORKOUT? GO LOG IT AT PUSH UPS LOGGER!

hope this helps, and lets do it