We are studying several novel steps toward real-life applications of terahertz waves, such as, i) palmtop terahertz-wave parametric generators, ii) printable terahertz sensors using metal mesh, iii) noninvasive detection of concealed drugs using terahertz wave scattering, iv) observation of MOSFET chips using an infrared laser THz emission microscope, v) monolithic Fabry-Perot resonator for the measurement of optical constants in the terahertz range. In this paper, we introduce some of our recent activities.