Pedestrian Tunnel near the Central Bus Station
The site has still has prices in Lats (LVL), pages are not updated since long long time ago, but in any case it stays as it is as a nice souvenir to old times.
Update December 2013:
The paintings do not exist in the tunnel anymore
Probably they were removed since the tunnel was renovated.
Pedestrian Tunnel was renovated and opened on 2008. It is named after local mobile prepaid card "Zelta Zivtina" (it was sponsored by Tele2 mobile operator). Young artists could take a part in competition after which the best 8 were chosen to make their paintings in the tunnel joining the Old Town and Central Market area.
Very nice "exhibition" and for free! :)
In Latvian "Zelta Zivtina" means "Golden Fish" maybe that is why there are some fish in the wall paintings.