Yes, there are two kinds. Intermatic makes one that is purely mechanical (you can hear it ticking when you turn it). This is cheap and effective. There's also an electronic one that will do 15-30-45-60 minutes, also intermatic. I've got these all over the place (I put one on the receptacle on my wife's dressing table so she doesn't leave her straightening iron on).

Both of these will work just fine with a bathroom fan. The electronic one however requires that there be a neutral in the box (which some switch loop installations do not provide). You can tell this if you pull the old switch out. If there is a white wire there that is NOT connected to the switch, you're good.

Both of these timers are available at the major home centers.

i, a teenager, put one of them on the light in my room in paralell with my light switch. when i am only to be a minute, i use the timer. when i am going to be awhile, i use the switch.

Lutron has fan timers that don't need a neutral and come in several colors.

One thing you need to check for is whether the timer needs a neutral. Some timers need a neutral wire and will not work in all switch situations.
A timer that does not require a neutral will work in all situations. Special timers are required for three way switches.

when i do a loop switch, i use 12/3g so i have a neutral

An occupancy sensor might be a better idea. This way he does not even have to turn on a timer. Everything is done by itself, and the lights will go off a few minutes after he leaves the room.

You could always do what my Dad did -- a nice smack in the buttocks. It didn't take long for us to figure out we needed to turn off the lights when we left the room. :-)

an occupancy switch requires a neutral.

Smithy, you'd be impressive if you had a clue.
Since you don't have a clue you are just another annoying kid who thinks they have a clue.

Not nearly all require a neutral. Leviton, probably the most popular brand, does NOT require a neutral.

Here is a link that might be useful: Something for Smithy to peruse

the ones i was looking at did.

So you flatly write: "an occupancy switch requires a neutral." ??

Dude, you need to get your facts straight and STOP posting just what you know from your staggeringly little experience.

YOU ARE NOT A PRO!!! STOP posting like you are one.

SHOUTING probably won't do any good. A pseudo admin. approach is likely to be equally ineffective.

I think I'm going to take a break from this board for a while and go install a QO panel someplace.