Speak with James Garrett at the Atomic Wrangler to start Wang Dang Atomic Tango then Recruit Old Ben (50 speech check) who will then run to the Wrangler and sit at the bar. Talk to him and you will see the speech option is still present.(might not work on patch 1.01 haven't tested)
After you complete the quest The Moon Comes Over the Tower you can speak with Emily Ortal (just outside the Lucky 38) about the "First attempt" to bug the tower. Currently you may ask her about it an unlimited amount of times.
Asking Angela Williams her opinion of Dr. Thomas Hildern leads to a low (25) speech check. This can be repeated at will for XP or this achievement. (Might require certain states of There Stands the Grass- works in 1.1.1 just after accepting the quest, when she tells you about Keely)