Strong winds driven from the surface of hot, massive stars create large interstellar bubbles and intense wind-wind collisions in binary systems and star clusters. These are observable across the EM spectrum from radio to TeV gamma rays. Bow shocks around runaway massive stars have been proposed as useful laboratories for investigating diffusive shock acceleration on account of their time-stationary structure, but so far only one non-thermal detection has been made in radio and none in gamma rays. We have started a radio survey of bow shocks with the VLA and Effelsberg. The first results confirm detection of non-thermal radio emission from BD+43 3654, and discover non-thermal emission from the Bubble Nebula (NGC 7635) around the star BD+60 2522. Simple arguments are used to constrain non-thermal X-ray and gamma-ray emission. I will also show 2D and 3D simulations of the Bubble Nebula, compared with the multiwavelength data, to gain a better understanding of this iconic nebula. If time permits I will show some preliminary work on 3D simulations of colliding winds in binary systems.