I currently have 4 bikes, none of which are for loaning to the untrained.

-caad10, with look Keos. Road race bike.
-felt tk2, with Keos. Track race bike. Obviously brakeless.
-an also brakeless fixed gear, with Time ATACs. (right, right, brakeless. dont judge. this is not the place for such discussion) My townie/beater/winter trainer/everything else bike.
-a crappy cruiser I won, but I'm trying to sell the damn thing.

One of my roommates (the not so bright one, who doesnt bike, and I dont like all that much anyway, because he's kind of a tool) only sees this as "I have 4 bikes," and keeps insisting that I let him ride one of mine so we can "go for a serious ride together" to like salem, MA or something. (~40 mi round trip from my house). He also insists that he's "pretty fit, he should totally be able to keep up!" (honestly, he is pretty ripped, but as far as i know, its all lifting so he can look good, with minimal cardio).

I'm out of ways to explain to him that he could not keep up, and even if I matched pace with him, there are practical reasons why he can't/shouldn't ride any of my bikes as an inexperienced cyclist. Sure, he could always ride the cruiser, but I wouldn't let anyone ride that for 40 miles straight, because, well, its a cruiser. He doesn't understand this concept either...

Most of all, I just don't want to hang out with him.