I just signed up for the the hundred push up challenge on this site done by Steve Spiers. Even though I have been pretty regular at doing the push up routine, I also wanted to work on core strength as well.
I emailed the Steve and asked him if there was a similar site for dumbbells. He sent me this site.
I wanted to embed this into my blog for convenience, so here it is. The guy in the video is Matt Tegenkamp, a record holder for the two mile run, and who is now at the Olympics competing in Bejing.
Good luck Matt, and thanks Steve.
I have only been doing the push ups for two weeks, but I can feel they are working.