End of the Metaverse is a very promising and interesting grid. Owner is BladyBlue Bommerang and she is doing a great job with it. Quote from G+:
“The end of the metaverse is a community run virtual world running on the opensim platform. EndMeta features a free mainland continent for residential and commercial use and hypergate-capabilities. Viewer URL is http://endofthemetaverse.us:9120 Hypergate address: endofthemetaverse.us:9120:Street
Get your own hypergate-enabled region connected to endMeta”
She also have a mainland with some free houses for new residents, very generous indeed.