Using electroencephalographic signals (EEG) for music creation has a long and distinguished history. Here, we introduce MaxMuse, an open-source streamlined system combining a low-cost, consumer-grade EEG headset (Muse2, InteraXon) and a widely used real-time graphical programming language (Max/MSP, Cycling'74). Pilot benchmarks show that the system is appropriate to process so-called "alpha waves", often used in brain-computer interfaces, but also auditory-evoked responses. Overall, we suggest that MaxMuse may facilitate novel interactive musical applications for which EEG signals can easily be collected from the composer, performer, or even from the audience.