1) A 50-50 is a skateboarding/snowboarding trick where you jump on to a rail, and grind the rail with your body parallel to the rail. This trick is the base for 5-0s, Nosegrinds, Crookeds, and Salads.

2) A 50-50 on a pipe is where you come up to an Axle Stall at an angle, and get on to the coping in Axle stall style, then you slide along the coping a little, then you drop back in.
50-50s are a simple, yet tight trick.
by Ricky Benda May 24, 2005
The 50-50 is a very mutual and sexual act performed by two people. To perform the "50-50" you will need to have a tub of Nutella and an anus. Scoop out a reasonable amount of Nutella onto the finger and insert into the anus. Allow 5 minutes rest and then with your tongue, lick inside the anus. There is a "50-50" chance that poo or Nutella will come out.
"Hey mum, can I 50-50 with the Nutella this week?"

"Hey babe, I was wondering if I can 50-50 you tonight?"

"The last time I 50-50'd someone I got poo on my tongue!"

"I'm not too hungry tonight. I might just have a 50-50."
by Mclanky Andrew November 3, 2013
Game played when you are unsure if you're going to fart or shit. The probability is usually equal.
If you pull my finger, we'll play 50-50.
by Joel TK May 25, 2005
When a woman give a man a hand job but with her feet
dude you know that chic from the bar yeah, well she 50-50'ed me under the table last night
by Collin Danaher March 30, 2006
equally or fairly shared
After they determined what the prize was worth, they split it 50/50.
by The Return of Light Joker August 29, 2009
A 50/50 is when you pay a prostitute to perform intercourse and follow it up with oral sex. Please note the order can be changed to suit the situation, or the patron.
As we drove down the street, my buddy yelled out the window at a known prostitute and asked "how much for a BJ and a Lay?". The prostitute replied "a 50/50 will run ya $35!".
by Street-Walker A June 24, 2010
A girl that appears good looking from either A) going by her at 50 miles per hour, or B) 50 feet away
Did you see that standing on the side walk? She was gorgeous!
We were on the highway, she was probably just a 50/50
by ChubbyPuppy August 22, 2011