Israelis of all ages and tastes take their weekend fun and socializing very seriously. Young people especially like to party with all their energy, especially those under 21 who are consigned to the army during the rest of the week (Israeli men and women continue to serve a mandatory three-year period of service until they reach their 21st birthday). 

There is little evidence in Tel Aviv of Shabbat as a time of quiet rest and prayer: in fact, nightlife is at its most vibrant after Shabbat starts on Friday night (the working week runs from Sunday to mid-afternoon Friday), while Thursday is another big night out. It may seem strange to those from other countries, but drunkenness is extremely rare - most Israeli kids think it is sad and uncool to drink alcohol. There is no bar-hopping or pub-crawling and while there is plenty of exuberance and noise, violent behavior is almost unheard of in Tel Aviv. 

Clubs and pubs come and go fast, with famous names disappearing overnight. Allenby Street is the central spot for bars and clubs, with more than 20 clubs within one small area, offering house, funk, disco and techno. There are a number of gay venues. The scene here looks like Amsterdam, with a very international crowd keeping very late hours, sometimes aided by various stimulants. As in most cosmopolitan cities, the dress code varies from one club to another; in Tel Aviv, jeans and T-shirt or smarter casual wear is the norm almost everywhere. The chic and stylish ones, though, employ a 'selectorit' - a daunting doorwoman who decides if she thinks people are cool enough to come in. For a more sophisticated or older crowd, plenty of other venues offer cabaret, as well as rock, jazz and folk music. 

Bars are usually open and licensed until 0300/0400, while clubs keep their doors open until 0600/0700. As a rule of thumb, most clubs in the city start to warm up after 0200 and do not peak until 0400. The legal drinking age in Israel is 18 years, but drinking to excess at any age is generally unusual in Israel. Anyone who becomes intoxicated through drink will be shunned - and probably thrown out. 

Source: http://www.worldtravelguide.net/city/125/nightlife/Middle-East/Tel-Aviv.html