UPDATE 1-'Hangover' gives Murphy a headache at box office

* "The Hangover" leads box office for second weekend

* Eddie Murphy bombs with "Imagine That"

* "Terminator Salvation" top film overseas (Updates with studio comments, sales for new film "Moon," foreign data)

By Dean Goodman

LOS ANGELES, June 14 (Reuters) - The party kept rocking for "The Hangover," the first big surprise hit at the North American box office this summer, while Eddie Murphy suffered a headache with his second consecutive flop.

According to studio estimates issued on Sunday, "The Hangover" led the field for a second weekend with ticket sales of $33.4 million across the United States and Canada. The raunchy comedy with a little-known cast becomes the first movie to retain its crown since "Madea Goes to Jail" in February.

The film also took just 10 days to hit the century mark -- $105.4 million, to be exact -- setting a new record for an R-rated movie. The old mark of 11 days was set last year by "Sex and the City."

Industry pundits expect "The Hangover" to hit $200 million -- not bad for a movie that cost a reported $31 million to make. The action revolves around three guys struggling to remember what happened at a wild bachelor party in Las Vegas the night before. It stars Justin Bartha, Bradley Cooper and Ed Helms, and was directed by Todd Phillips of "Old School" fame.

The film, from Time Warner Inc's (TWX.N: Quote, Profile, Research) Warner Bros. Pictures, easily fended off a pair of new entries boasting some major star power.