In Old Riga the logical place to start is Peldu iela, which is not only nightlife central, but also home to two great live music clubs. Folkklubs Ala Pagrabs offers free live music nearly every day of the week and you can usually hear anything from Latvian folk and world music to blues, jazz and even local rock. It also offers a great selection of Latvian food and drink. Just across the street is Trompete (Trumpet Taproom) where, not surprisingly, you can listen to free jazz and blues music while enjoying a fine wine and refined international cuisine. The nearby Egle summer terrace also offers free live music nearly every day (April - September) on the small stage and larger free acts on its main stage (reserve a table). The alternative bar Depo also offers regular concerts by punk rock, ska and metal bands for a small fee.
There are also plenty of options in Riga’s city centre including the self-styled KKC Culture Centre is a hipster haven home to live concerts by experimental musicians, jazz acts, rappers and DJs and is a great place to see a show outdoors for only a few euros. Drinks are plentiful and snacks and salads can also be had. Finally, there are also some great seasonal options farther afield. During the summer months you can take in free live open-air concerts at the Kalnciems Quarter on the other side of the river every Thursday evening at 19:00. Food, drink and great ambience are guaranteed.