Actors/Acresses playing multiple parts

[DJ Doena]

After Ross and Rachel broke up (for the first time IIRC - the "we were on a break" incident)

OK, it was before they even got together.

[Tom]

Slightly off-topic but I love this snippet. This is basically Dr. House before he was Dr. House.

When I think of Hugh Laurie, I don't think of House, but for me he will always be George from Blackadder

On topic: In each series of Blackadder, the actors play different incarnations (relatives) of the same character in different time periods.
Here Hugh Laurie as George in "Blackadder Goes Forth" which is set during World War I:

[Tom]

And "Red Dwarf" has Ace Rimmer, Dwayne Dibbley and other characters from alternate realities.

[Mustrum_Ridcully]

Another example:

Cloud Atlas

Haven't watched it yet, so can't say anything about the quality.

[DSig]

To me, Cloud Atlas is a monster film.  You have to enjoy films with multiple time periods going on but if you  can enjoy that you should love this film.  Tom Hanks was very very good in this.

[Achim]

After Ross and Rachel broke up (for the first time IIRC - the "we were on a break" incident) Rachel started to date a guy by the name of Russ and her friends couldn't help but notice that he has a slight resemblance to Ross wich isn't that suprising because he was played by David Schwimmer as well.

Thanks. After your explanation I seem to vaguely remember such incident.