My favorite, though it relies on finding someplace to prop your camera (since you did say "you forgot to bring your tripod"), is multi-minute exposures (5-15 minutes at about f/8, usually) on Fomapan 100, developed in Diafine. The terrible reciprocity of the film, combined with the developer compensation, keeps the streetlights from blowing out.
For higher-contrast "ordinary" dark situations, maybe HP5+ at 800 in Diafine. I've also gotten some good results with Delta 3200 at 3200 in HC-110, but the grain is enormous and the film is expensive. Or there's always Tri-X in Donald Qualls's bizarro developer "Super Soup", which at EI 6400 looks reasonably normal and even at 12800 isn't unbearable (in medium format, anyway).
-NT