G protein–coupled receptors (GPCRs) are a large and ubiquitous class of membrane receptors that are important targets for drug discovery. Until now, most assays of GPCR function have been performed in whole cells or in transgenic animals, neither of which are amenable to high-throughput scale-up. In this issue, Vogel and coworkers have come up with an alternative platform by successfully immobilizing GPCRs on a chip surface and measuring their activation directly by surface plasmon resonance (SPR) (see p. 1105 and p. 1060).