Imagine Nightclub is one of the best off resort nightlife options in Punta Cana.
Located inside a cave it's about a 15-30 minute ride from most resorts.
There are 4 different caves each with their own ambiance. The club regularly holds themed events, check their website for details (google "imagine punta cana" or check out their facebook page) Imagine is popular with tourists and locals alike. I'd definitely recommend it for a great night out.
You can purchase Imagine Packages via your tour operator or hotel tour rep.
Cost: 55$US includes free drinks/open bar for one night until 4am, one weeks free transportation to and from your hotel on their shuttle bus, one weeks free entry.
Arriving with your own transport/taxi - 20$US entry fee includes one free drink per person.
There are plenty of taxis waiting outside the club for those who have arrived independently or those who wish to leave before the 4am pre-paid shuttle bus (you will need to pay for a taxi).