If you feel self-conscious about having really skinny legs, you need to do some training to bulk them up. This infographic features 19 exercises you can do to take your legs up a few sizes. A Skinny Person's Guide to Gaining Weight
This is a highly effective leg workout routine that can be performed in the comfort of your own home, without having to visit a gym. However, it does utilize a few pieces of basic fitness equipment that can generally be found in any home gym.