While all the attention is focused on the superstar megatreks, there are always some tours that rise up and makes a lasting impression. These "sleeper" tours can take place at any level, indoors or out, clubs, arenas, theaters, ballrooms or amphitheaters. Basically, we're talking about tours somewhat under mainstream radar in the spring that, come August, will be ubiquitous in the blogosphere and in the shared consciousness of the live-music fan universe.

By their very nature they're difficult to predict, but we'll make a run at it here.

1. R.E.M.

A revitalized R.E.M. is enjoying its best ticket sales in years in the wake of the band's well-received "Accelerate" album. With Modest Mouse and the National supporting in North America, the tour, which began Memorial Day weekend in Vancouver, plays a wide range of venues before heading to Europe. Early signs point to big success.

"Our first-day sales were better than what we ended up with on the last tour," R.E.M.'s longtime agent Buck Williams says. "There's a lot going on sale right now, and we're [at] 8,000-12,000 tickets almost everywhere."

Asked why the uptick, Williams credits the new record and renewed vigor from the band. "They've gotten substantial airplay, and we haven't been getting that in the U.S.," Williams says. "The band is proud of this record and they're playing a lot of it on tour."

Promoters have noticed the band's enthusiasm. "People are excited about R.E.M. because R.E.M. is excited about R.E.M," says indie promoter Seth Hurwitz, who has R.E.M. booked June 11 at the Merriweather Post Pavilion in Columbia, Md.

Williams says the band will return to North America in the fall for more shows, including New Orleans' Voodoo Fest in October.

Click here for the full list of tours poised to make a lasting impression this year.