I've been building up to 200 crunches. I was doing the Greater Waterbury YMCA ab challenge last month and the last day of the challenge stopped at 160 crunches. I thought to myself,, I'd like to do an even 200 of them. So I kept going, increasing 5 per day until I reached 200 today.
In addition, I'm doing their other ab challenge, a planking challenge. It's five different kinds of planks, increasing by 5 seconds each day. There's only 2 days left of this challenge. Today, I held the planks for 50 seconds each.