3 Weeks
I've had the pull-up bar that long, and have worked my way up to 18 pull-ups and 40 push-ups broken into 4 sets (5, 5, 4, 4 for pull-ups, 10 each push-ups).
My arms and back are beginning to look pretty impressive immediately after exercise and I'm getting definition in my abs even though I haven't started doing sit-ups yet. My chest doesn't seem to be increasing as rapidly, but pull-ups and push-ups don't work it out as well as other exercises would.
After I've rested enough my muscles don't look nearly so impressive, but my arms are noticeably larger.
See more progress on: Be “Ripped”