Night time shows:
-Cirque de Soleil @ DTD. A must see. It's a little pricy but worth every penny.
-Polynesian Luau @ Polynesian Resort. A Disney classic recently revamped.
-Hoop-Dee-Doo Review @ Fort Wilderness. I've never made it there but everyone I know that has seen it has loves it (including one of the most jaded, anti-Disney people I know).
Keep in mind that the luau and HDD are generally geared towards kids (as are many things at Disney. However they are still very enjoyable for kids of all ages.
Other night time activites:
-Pleasure Island. 7(?) clubs for the pric eof one admission. Everything from 70s dance music to a comedy club. Definitely check out the Adventurer's Club (and stay and see one of the performances in the outer rooms) and the Comedy Club. Two of the clubs require you to be 21 to enter (BET and one other). The others only require you to be 21 to drink alcohol. Many nights can be spent at PI.
-Fantasmic @ MGM. A must see held just after park closing (usually). Do not miss.
-Illuminations @ Epcot. Help at around 9:00 pm - 9:30 pm. Check the schedule and don't miss.
-Fireworks in the Sky @ MK. A great fireworks show. Check for days and times on the Disney website.
-Electric Water Pageant @ Bay Lake. This is the lake between MK, CR, Poly, and GF. See it from one of those resorts beginning around 9:00 pm at the Poly (I think). It's kind of neat to watch, especially if you have 14 days to do things.
-Boardwalk. Fun activities on the boardwalk, plus the Atlantic Dance Hall, Jellyrolls, and the ESPN club. Sorry, I'm not sure what the minimum age is for all these clubs.
Dining Options:
There are way to many to list here. Each deluxe resort has at least one (and usually more ) good sit down restaurant. Each moderate resort also has a sit down restaurant. Each park has a number of good restaurants, with Epcot loaded with them. Even DTD has good eating. You really can't go wrong with dining at Disney. Pick what appeals to you and give it a try.
At Epcot DW and I ate at Le Cellier in Canada. It's a great steakhous (with good fish also). It's a nice atmosphere for adults. But try something new and different as well like the Moroccan or German restaurants. France has great restaurants and a great bakery.
With 14 days you'll get to do a lot of the night time activities and eat at many restaurants. I'm jealous

.
Have fun.