Whats a really good arm excercise

I need an arm excersice that I could do every day withouhgt waysting much time, I have really good abbs but my arms, mmm not so good good.

atleast 20 push ups a day...the guys way and about 100 jumping jacks. but if your not use to it, start off easy, maybe 5 push ups and work your way up.

chin ups

The best thing to do is to get dumbells. I reccomend doing what are called 21's.
Get some dumbells, maybe 10lbs for you, bring the weights to your waist (pinky fingers facing your waist) so that your upper arms are going striaght down. Then curl your bicepts 90 degrees upward - making an L shape. Curl half-way up like this seven times. Then, on the seventh time, curl all the way up as you normally would (hands nearly reaching your shoulders), but - as you curl downward you stop at the 90 degree L mark, going all the way up (almost toughing your shoulders) then stopping at the 90 degree mark ( L shape of your elbows pivot ) seven more times. After this, go ALL the way down (so that your entire arm is straight) then all the way up (so that your hands come close to your shoulders) seven times. Doing these three things seven times gives you whats called 21s - an excellent bicept workout.

the answers above are really good but if you want something really easy
try holding your arms out for a long time... ull feel the burn