OpenQuest is the "rules light-ish" sibling of Mythras (and both are descendants of RuneQuest and Basic Role-playing). It's a great system, one that I've played in the past and would be happy to do so again in the future (although I haven't been able to read the 3rd edition version yet). Based on my experience with it, I highly recommend OQ for anyone who wants a simpler d100 fantasy system alternative to Mythras.
And now D101 has made available for all the OpenQuest SRD. Enjoy!
