stands for Optimal Golomb Ruler, the shortest possible Golomb ruler a given set of marks. OGR-24 is the newest distributed computing challenge, searching for a (gasp) 24 Mark Golomb Ruler. Also, as noted in the node below, OGR-25 has commenced. Its the same deal really, just another n++; situation. My personal opinion is to crack that which I've been working on for ever (RC5) first, then worry about other things... actually, I was really all about because of encryption really, so maybe my cycles will be spent elsewhere after RC5.