The Zeppo

Mr. White, Clark, Lois and Jimmy Olson are all character's from the Superman comics. Xander compares himself to Jimmy Olson when it is suggested that he hang back from the battles. Jimmy Olson was a cub reporter at the paper and often worried about getting experience when all the best stories went to Clark and Lois.

As Xander's response indicates, the line is also a Michael Jackson song.

A reference to Zeppo Marx. Zeppo was certainly the least memorable of the Marx brother's comedy group. Though some will certainly argue that he wasn't useless as Cordelia contends Xander is to the Buffy-gang.

Xander refers to his new car as his "Thing" which could be used as a euphemism for a penis.

Buffy suggests the demon sisterhood could emulate athletes in celebrating victory by pouring gatorade on each other rather than eating their foes.

It's not clear if Xander made the reference intentionally but Up With People is a youth organization that performs traveling shows to "build understanding and cooperation among people of different cultures". Faith is in a way introducing Xander to a whole new world.