Plenty of New York jazzers are out there seriously investigating Eastern European music these days--and in their midst Slavic Soul Party! have distinguished themselves in part by not taking themselves too seriously (hence the exclamation point). Still, as the quintet's recent debut album, In Makedonija (Knitting Factory), proves, in the past five years the musicians have learned to play Balkan party music with striking facility. A couple years ago the group--leader and percussionist Matt Moran, accordionist Ted Reichman, clarinetist Chris Speed, trombonist Curtis Hasselbring, and cornetist Rossen Zahariev, all fixtures on the downtown scene--received a grant from the Trust for Mutual Understanding to travel to Macedonia, where the album was recorded. The group's repertoire draws on Gypsy and Greek musical traditions, where complex, high-velocity unison lines unfold in long zigzags over tricky rhythms. The best-known Macedonian proponents of this music are considerably better staffed: just the horn section for the Kocani Orkestar, for instance, has more members than SSP!, and size alone gives them more oomph and propulsion. At times SSP!'s stripped-down lineup makes them sound a bit anemic, but they're incredibly resourceful at adapting the contrapuntal material. SSP! isn't a purist outfit; its jazz pedigree shows in a surprisingly sympathetic version of Duke Ellington's "Blue Pepper," from the composer's Far East Suite, and on certain tunes, like "All Up and Down," they veer off into well-executed patches of free-sounding play. The album also includes a few bits of fun audio verite (an interview on a Skopje radio station, field recordings of local performances) that emphasize the group's good-natured spirit. Tuesday, May 21, 8 PM, HotHouse, 31 E. Balbo; 312-362-9707.