The two biggest events in Lençóis [1] take place in the winter. Throughout most of mid–late June, the town gets into the swing of things with the typically northeastern Festas Juninas, the feverish high point of which is the Festa de São João on June 23 and 24. Expect lots of corn-based delicacies, homemade fruit liqueurs, smoking bonfires, processions, and forró music.
In August, the town resembles a latter-day Woodstock when it hosts the Festival de Inverno de Lençóis, a musical festival that lures some of the biggest names in Brazilian popular music.
Links:
[1] http://www.moon.com/destinations/brazil/bahia/chapada-diamantina/lencois