A2KLAU,
OGR is the other contest currently being handled by Dnet. The client does both, and Team AnandTech has teams for both. You can rotate back and forth between the two, or do one or the other exclusively.
As for RC5 being more popular; there are certainly more participants, but that's a function of the fact that it's been around longer then OGR. They're both a lot of fun, and TA is ranked at, or near the top in both.
Russ, NCNE