Stamp of approval

In Ireland, you’ve arrived when you’re on a postage stamp. Altan arrived in 2006 when the traditional Irish band was honored by its government with a stamp. The award-winning group actually arrived on the scene as a band 25 years ago, and celebrates the anniversary with a new album (and hopefully some cake). Head to Somerville for songs by vocalist/fiddler Mairéad Ní Mhaonaigh and fellow fiddler Ciaran Tourish with accompaniment from Dáithí Sproule on guitar, Dermot Byrne on accordion, and Ciarán Curran on bouzouki. 8 p.m. $28. Somerville Theatre, 55 Davis Sq., Somerville. 617-876-4275. www.worldmusic.org