My first ever manned landing, on Mun; everything went well, I established an orbit round Mun, then shortened this and descended, landed, perfect! Jeb got out, one small step for a Kerbal etc. He went for a walk. Took some photos. Wonderful. After a while I decided it was time to head home, and went to put him back into the lander. This was when I realised I'd put a battery right under the door and he couldn't climb back up. This was also before I realised Kerbals carry a portable RCS pack with them. So I spent the best part of 30 minutes desperately trying low-gravity leaps at varying speeds and from various locations (which at one point resulted in him spending 5 minutes tangled in the struts and fuel-line of one of the drop-tanks) until I timed it right and I was able to hit 'Board' in the fraction of a second it flashed up on the screen, and Jeb was able to return home to his loved ones.