This week’s agenda was written in part by DCist contributor Matt Sedlar.

MONDAY
>> Sure, we mentioned it in last week’s agenda. And in the weekend picks. But a co-headlining tour of Belle & Sebastian and The New Pornographers is a pretty big deal. The DCist contingent will be there tonight, and hopefully we’ll find out the answers to those burning questions — whose fans will make for a better crowd? Which band has a bigger fan base in D.C.? Will we really be seeing The New Pornographers, or just the Carl Newman show? All this and more tomorrow. As for tickets, see what Craig has to offer, the show’s been sold out for quite some time. 7 p.m.

TUESDAY
>> Dust off your old Bauhaus T-shirt and fishnet stockings and head over to the 9:30 Club for Sisters of Mercy. Warming up the crowd is the psychedelic/space freak out collective from Los Angeles, The Warlocks. Everyday is Halloween, indeed. 7:30 p.m. $35.

>> Everyone’s favorite green-coated, ethnic-pride-soaked holiday is right around the corner. Start celebrating early with Scythian‘ Celtic music at Iota. No, the guys in Scythian aren’t all Irish. But their music, crafted by classically trained musicians from Virginia, is all fun. Every person we know who’s seen these guys has come out a true believer, so go see what all the fuss is about. 8:30 p.m., $10.