Yes, Liz Lemon once dated Jon Bon Jovi. He shows up on the Valentine's Day episode.
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Elizabeth Banks guest stars on this episode of 30 Rock. She plays a love interest of Jack.
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Liz Lemon has an interesting history of dating. A few of her exes are seen here.
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30 Rock Season 4 Episode 13 Quotes

Your ghost is going to see some disgusting stuff.

Frank

Valentine's Day is a sham created by greeting card companies to reinforce gender stereotypes.

Liz