Did you hear the one about the two serious policy wonks who walked into a comedy club?

The punchline is that Democrat John Street and Republican Sam Katz were funny enough at the annual Stu Bykofsky Candidates Comedy Night charity event last night to give Philadelphians a glimmer of hope that the next four years won't mean soaring deficits of humor at City Hall.

Street, who was once better known for a punch than a punchline, was surprisingly adept at standup, but he got his biggest yuks for auctioning off a life-size photo of Mayor Rendell scrubbing the bathroom floors of City Hall.

"C'mon, Ed Rendell will not be getting down on his hands and knees and cleaning any more toilets - unless it's the governor's office," said Street as he upped the charity bidding for the giant photo to $3,000. (The buyer was radio tipster Kal Rudman.)

"Where's Marty Weinberg?," Street exhorted, searching the crowd in vain for his former Democratic mayoral rival, who'd raised some $6 million for the spring campaign. "You told me that you would do anything for me."

Katz, whose sense of humor has improved in the 1999 campaign even more than than his chances of winning in November, also found that it was easier to make fun of the mayor than of his opponent.

He said that after the May primary his advisers told him that voters wanted the next mayor to act just like the popular Rendell.

"So now I haven't walked by a table of food for the last three months without stopping to sample the wares," Katz quipped.

After the recent flap over Katz posing for Philadelphia magazine with upturned middle finger, we'll kindly not detail the one he told about the taxi driver and the hooker.

OK, so it wasn't George Carlin, or even George Jessel, but it wasn't so bad that anybody threw a battery on the stage.

And it was for a good cause.

This was the ninth year that Bykofsky, a Daily News columnist, has organized the event as a fund-raiser for the Delaware Valley Chapter of the Variety Club, which buys medical equipment and hearing aids and runs a summer camp, among other things, to aid disabled kids.

This year, Bykofsky sold $14,000 in tickets to pols and other bigshots, a record, and the Rendell photo auction and a couple of other raffles pushed the total take since 1991 past $80,000.

Besides the two major-party mayoral hopefuls, the crowd at the NewMarket Cabaret Theater near Headhouse Square heard the comic stylings of City Council at-large candidates. These included a slightly off-color Jim Kenney; Angel Ortiz, who got more laughs when he spoke Spanish; and Thacher Longstreth, who recalled the profuse praise he received from a voter who then said, "Goodbye, Mr. Dilworth."