Blazar variability -- expect the unexpected

Abstract

Despite significant progress in both data taking and the development of theory, blazars keep offering surprises. While many frequency bands are now covered by long-term monitoring efforts on at least a few selected sources, blazars remain unpredictable and the same source may exhibit vastly different behaviors. Here, an overview is given about four selected sources, namely 3C\,279, PKS\,2155-304, PKS\,1510-089 and CTA\,102. All of them exhibited, indeed, highly unexpected events