[Request] Jokes About Time Travel.

Back in the late 90's - early 2000's, there were time travel jokes floating around the internet that were clean yet funny (to my 15 year old self). They all started out similarly. I remember one that went something like:

"When traveling back in time, don't hang your arm out the window. It'll turn into bone."

There was another that went something like...

When traveling back in time, don't make eye contact with those traveling toward you because..."

...but I don't remember the punchline. Are these familiar to anybody?