I get a lot of hits on that search term, which is kind of cool. This year I have three pots, this little one that graces the windowsill over the kitchen sink and two big ones in the living room. This one won't produce a salad, but there is enough lettuce available for a sandwich or a snack pretty much all the time. The big pots are more productive.
Anyhow, if you want to grow lettuce indoors it is ridiculously easy. I think a nice pot of well-started leaf lettuce would make a cool Christmas gift for almost everyone. It's not like everybody already has one or anything.
Alas, I never seem to think of starting any for gifts until it is much too late. You could probably get some going for this year if you started right now though. Lettuce is quick to sprout and you can begin thinning leaflets almost as soon as they come out of the ground.
You can read previous posts on indoor lettuce:
Here
And here