Nightlife in Reykjavík essentially means two types of establishments: pubs, and nightclubs with dancing and live music. Icelanders tend to dress up for nightspots, but visitors can get away with being a bit more casual. On weekends, unless you start before 11 pm, be prepared to wait in line, especially if summer weekend weather is good. Avoid downtown after midnight during the first weekends of summer, when excessive drinking can result in some raucous and aggressive behavior. Suffice it to say, Icelanders party en masse.