I've got neighbors that served in the Liberty Jail. They would be tour guides there 4 days a week. The other three days they could do what they want. He actually bought a boat to go fishing in his off days.
I know another couple who works with Deseret Land & Livestock checking in on kids doing pioneer trek.
And another couple serving a mission that consists of working at the PCC a couple of days a week and teaching a class at BYU-Hawaii one day a week.
I don't think a proselyting mission is for me. But there are service missions like those I just described that might get me.