I mostly play mobile, and sessions are usually 1-5 minutes. I play mobile games multiple times daily.

PC games - 3-4 hours. Only a few times a year do I play PC games though.
Handheld/console - 30 minutes to 2 hours. Probably 3-5 times. Week.

These says 2-3 hours is normal for me to spend an evening.

When I was a kid and had more free time I remember 10+ hour play sessions in the dead of Winter playing an RPG.

Back when I use to play Runescape it was 6 hours straight. Now, sometimes its barely an hour.

Usually a few hours, and then a break.
But sometimes they can last hours and hours (like 8+).

Usually no longer than an hour. But I will again play whole nights through once my son gets a little older and stuff.

would you look at that, about 2/3 of people play games for less than 3 hours a day!!!!!! And since this is a gaming forum, where people tend to be more of enthusiasts, its highly likely that people on this site play more than the average gamer so for most people its probably like 1-2 hours a day.

Usually 30 minutes to 2 hours, sometimes a bit more than 2 hours (when I've got a new game).

The longest I've ever played is around 3 (maybe 4) hours straight.

Provided theres no activity in schedule... say, a sunday, around 6-8 hours.

what about an average day?

around 2-3 hours at most.