The nightlife in Vientiane is very laid back and relaxed. Beer is available pretty much everywhere, with the emblematic Beerlao, probably the best beer in South East Asia and the symbol of the country. Try out the Beerlao Dark to be sure, you will for sure be seduced if not hooked. To be sure, take time to read these articles of NY Times, or Best Beer HQ.
The local rice wine affectionately known as Lao Lao packs quite a punch. Have a few cocktails and watch the sunset over the Mekong at Spirit House, Bor Pen Nyang, Highlander or Chok Dee. If you miss a bit of Irish action, visit O’Gradys’ and try their in-house specialty, Seamuson.