This solution may become redundant if it is patched, but a quick fix other than the usual "Find 50 speech challenges, win 50 speech challenges"....
Go to Big Town, north of Vault 101.
Talk to Bittercup about dating and such.
Then go and find Pappy and do the conversation challenge with him.
As long as you have a Speech level of 35+, you should be able to ace this conversation, and you can do it as many times as you can be bothered to.
This is not a legit way to do it, but it's damn fast and you have unlimited exp.