Note this cheat requires 35 medicine skill.

After you gain access to the Vegas Strip and go to the lucky 38, talk to Mr. House for the first time. He will ask you to obtain the platinum chip.

After he is done start asking questions. Ask him "who are you Mr. House?", after he is done talking pick the "You appear to be computer, not man" speech option.

After that pick the medicine speech challenge to gain 35 exp and repeat this trick as many times as you want, although it only works until after you recieve the platinum chip from Benny.

This only works on an unpatched version of Fallout.