Thanks for the comments fat and rad, we'll likely say no but I'm still interested in learning if others have done something similar.
You mean loaning money? If so, not on real estate. There was a time though when one of my wife's college's friend's friend was admitted one of the top 3 MBA schools. The only problem was that he couldn't afford to go. His friend's friends started to solicit college friends (5 folks, wife included) if they could help "sponsor" him for a student loan. It started out that someone suggested each of us could loan him a couple of ten-thousands, with a "promise" for payback plus market interest. The problem was that this person was from China, with no credit, no assets here, nothing (hence why he couldn't qualify for a student loan). I was sort of leary of this, but my wife was generally sympathetic to students from her college. Being a foreign student herself, she could relate what a great opportunity it was and how it would be terrible if the person couldn't go, so she was considering helping the guy out. And since she was planning to donote to her alta-mater anyway, we thought well why not just cut out the middle man and help an actual person out….We probably would have gone through with it except other folks bailed out, and it somehow ended up that his friend's friends were trying to get him a real student loan, co-signed by the rest of us. At that point, we bailed out. The way we got out without upseting her friends was that I just told her to tell them that "my husband is a cheap american bastard, and won't cosign any loan without collateral…"
In hindsight, I don’t know what we were thinking. While I feel bad that i think the guy didn’t end up going, it’s really not our responsibility to bail everyone out either.
There are the other friends that occasionally ask us if we would like to “invest” in some fund/asset/property/etc. The polite thing to say imho is, “gee, we’d love too, but were broke especially now with a kid”.