Just the TKTS

Everybody knows about the half price Broadway tickets booth in Times Square and sure the idea of seeing a show at half price is alluring but the lines there will eat up the best part of your day in the Big Apple.
What many tourists don't know is there is another booth -  in Brooklyn with practically no lines.  Here's what you do:

Take the "A" subway towards Brooklyn.  It is an express and you won't have to stop at every station along the way.

Get off at the "Jay Street" station.  When you get up on the street ask anyone where the Marriott Hotel is (it's only a block away)

And the ""TKTS Booth" is right behind the hotel.

It is open from 11:00 am - 5:00 pm Monday - Saturday.
You can purchase Matinee tickets for the next day on Fridays and Tuesdays.  It is better to go after 2:00 to get up front seats.
Just this last trip alone I saw:
Gazillion Bubble Show (Tooooooooooooooo much fun!)

Jersey Boys (dancin' in the aisles)

Nice Work if You Can Get It (with Matthew Broderick not an inch over 5'4", married to Sarah Jessica Parker and Gweneth Paltrow's mom Blythe Danner)

If you are patient everything goes half price eventually. 
I've been afforded the opportunity to see twice as many big shows at less cost than the traveling shows in my home town.