Cyclotron motion of electrons in a magnetic field, and the related resonant absorption of light at the cyclotron frequency, is probably the most representative magneto-optical effect, which is characteristic of any solid with a non-zero density of free charge carriers. In this talk, I will review selected results of cyclotron resonance measurements performed on various materials. These include systems which host conical features within their band structures (e.g., single and multilayer graphene, graphite, gapless bulk HgCdTe, HgTe quantum wells). In contrast to conventional systems with parabolic bands, such materials imply fairly complex, in general multimode, cyclotron resonance response, which allows us get relevant insights into their electronic band structures, as well as into particular elastic and inelastic scattering mechanisms.