The Brooklyn duo of John Flansburgh and John Linnel are something like a prime number–you could take all their influences and yet they’d remain, irreducibly, They Might Be Giants. What unites their eight-album oeuvre is an off-beat sense of humor, infectious melodies, and a quirky aesthetic that recalls early XTC. They epitomize late-’80s college rock with a loopy, unrepentant joyousness. While they’ve settled into cult-hood since, they remain a vital act, releasing their most recent album, The Spine, in July. Lincoln Theatre, Monday, Sept. 27, 8:30 p.m. $16. 821-4111.