Flex features a revolving line-up of "clubs." If you are into indie rock, drum and bass, break beats, hip hop, dub, big beat, illbient, house or soul flowered funk, then you will probably find a night that piques your interest.
The club is typically Euro Smoky but filled with lovely youth. Enter from the canal side and head to the left to get to the club. Head upstairs to check your coat, get a Red Bull and a drink at the bar and get ready to roll!
Don't even think about showing up until 10PM at the earliest as it seems that things really don't start cranking until late night.
Another interesting side note is that this club serves as a hub for activist resitance to the ultra-conservative "Schwarz/Blau" coalition.
Some highlight include:
Mondays -- Dub Club comes highly recommended, although I've yet to attend.
Wednesdays -- London Calling features indie and alternative rock normally with a hip influence.
Thusdays -- Sub is an amazing event every time with some of the wickedest, most ill drum n bass ("drum 'n' drama") shit I've ever heard!
Saturdays --- Revolving but features usually some of the world's greatest Techno (not the cheesy Euro Techno you're thinking of, but real, deep underground techno).