Rock Band 3 - 'Road Challenges' explained

In each Road Challenge, your band plays a series of gigs in a variety of locations and venues. By playing these gigs, your band collects spades – one for each star earned by playing a song. But each song also provides an opportunity to earn bonus spades. These bonus opportunities are expressed as gameplay objectives that vary from gig to gig. Here are some examples:

“Overdrive Overdose.” Earn your bonus by deploying Overdrive as many times as possible. It doesn’t matter how long each Overdrive deployment lasts - the greater the number of Overdrive deployments, the larger the bonus.
“Streakmania.” Build your bonus with each streak of notes (or vocal phrases) achieved by any member of your band. Consecutive streaks grow the bonus at an even faster rate.
“Share the Spotlight.” Band members take turns performing “in the spotlight.” When you’re in the spotlight, you’re under pressure to achieve a note (or vocal phrase) streak. Doing so hands off the spotlight to another band member. Your bonus grows with each successful hand-off.
“All for One.” If all band members play with high accuracy within a song section, your bonus increases. But if even one member fails to make the cut, then no bonus is gained - you’ll have to try again in the next song section.
“Overdrive Streak.” Here, you’re rewarded for using Overdrive without breaking streak. The more notes (or vocal phrases) you can streak while deploying Overdrive, the bigger the bonus.
“Overdrive Chain.” This one’s about deploying Overdrive for as long a time as possible. Band members can extend their Overdrive time by “chaining together” deployments - so long as one or more players is deploying, the chain continues to build. Longer chains translate to bigger bonuses, so coordinate with your band to time your deployments appropriately.