Have you heard about the BOINC Project? It's basically a program that runs in the background and gets activated when you're not using your CPU or GPU. It uses that processing power to do all kinds of interesting stuff, such as finding asteroids, find primes, analyze maps etc. etc. Cool things in general, and you massively help science. The program is easy and doesn't get in the way when you're using your computer.
A video editing program can probably take advantage of the extra power, but I don't know of any free good ones. After affects maybe but it isn't the easiest to learn. CPU mining will use the power of the i7, but I don't think it can compete with GPU mining.