Young partygoers, or those looking to recapture their misspent youth, should head straight for Royal City Avenue. More commonly known as RCA, this long, rather soulless road is one of a few government-designated nightlife zones. This means that the clubs found along it have the modest honour of being allowed to stay open, legally, until 02:00.
Even midweek it gets busy. However on weekends it's overrun with impeccably dressed young things, most of them locals in their late teens, early 20s. The vibe is young, the mood carefree, but with all the security and crowd management it feels a tad sanitised. Broadening the mix is a smattering of backpackers tired with Khao San Road and expats bored with Sukhumvit Road. Prices for entry and drinks are typically very reasonable, much lower than at many of Sukhumvit's trendier offerings.
Most clubbers attend one of the myriad venues playing hip-hop, R'n'B, house or trance, like Slim/Flix and Route 66. These are super-clubs by any standard, all vast sleek interiors, booming sounds systems, funky furniture, soft mood lighting and dazzling lasers. Many get so packed that all you'll see from outside come midnight is bodies squeezed up against the windows. Fortunately most have an enclosed seating area outside where you can find a table. Others like JazzIt push more than just hip-hop, regularly playing host to live bands and electro nights. And there's also Zeta, a girls-only bar catering to the city's blossoming after-dark lesbian scene.
In the old days RCA was a notorious magnet for underage teens, so today bringing ID is a must. All of the clubs will ask you for it as a matter of course - whether you look 17 or 27.
Also bear in mind that, with the music volumes set ear-splittingly high, RCA may not suit if you want to chat long into the night with friends. Not unless you're especially good at lip-reading that is.
RCA's House Cinema is a more culturally enriching option. Screening films from all the corners of the world this is the place to catch that Korean, Japanese or arthouse flick the bigger cinema complexes wouldn't touch.
Massage parlours with names like Poseidon, Caesars Palace and Emmanuelle are found scattered all along Ratachadapisek and cater mostly to those locals partial to a soapy rubdown or 'full service'. The reliably gaudy and garish neon signs mean you can't miss them. Then there's Ratchada Cabaret (opposite Soi 6), which offers a popular ladyboy show less well known to holidaymakers.
While famous for both of the above, Ratchada is also one of Bangkok's best-kept after dark secrets - a place where loud neon-lit drinking holes meet hordes of whisky sipping locals set on having a mostly wholesome time with their friends.
Much of the action takes place within a tightly packed cluster of music pubs, bars and clubs found in Ratchada Soi 4. Highlights here include Dance Fever, Zaleng, Rad, Hollywood, Baku, Kokok Pub, Pure Bar, Ivre, Gig Club and the very popular and well-executed Snop. With no entry fees it's a great spot for bar-hopping, although it can get frenetically busy, especially on weekends.
Prices for drinks are very affordable and some places close later then elsewhere in Bangkok.
Worth bearing in mind is that foreigners may feel something of an oddity here, although the locals knocking back watered down Scotch will make you feel nothing less than welcome.
Close by on Ratachadipsek Road is a beast of a club called Inch. Here eclectic futuristic and retro design touches combine to create two zones - both featuring the usual diet of mainstream hip-hop and live Thai music. Close by is another popular venue, The Baryan Tree, and a music pub called Pump Up.