If you are looking to take your pull-up exercises to the next level, then consider a pull-up station.  If you have a dedicated workout area, and aren't in a pinch for space, then a pull-up station could be an excellent addition to your workout program.

They typically occupy approximately a 4 square foot area of space and have a capacity of 300 pounds.  You can perform a number of exercises on a pull-up station, such as knee raises, leg raises, oblique bends, dips, pull-ups, push-ups, chin-ups, Lat pull-ups, and more.