Smack yourself in the head 500 times a day and your triceps and biceps will start to bulk up. I am the same age as you and am built from using weights. Take your ass to wal mart and buy a weider pro or even just a bench set, and do the major bulking exercises like bench and straight bar curls. I have a feeling your not playing sports and your just trying to "look good", but if you play sports like me you are going to have a more rounded workout regimen like power cleans, deadlifts, and squats. Any workout you do will be better than what you are doing now...nothing. Ride a bike, do pushups, chinups are the shit. Good Luck