When you are working with electronics or simply building stuff, you probably always end up testing one or several components for their faults or making sure parameters are within specs. Most of those tasks can be done with multimeter. Obviously any multimeter have resistor and capacitance testing modes. Anyway, there are more components that may be tested and using multimeter might require some setup. Baweja_akshay have built pretty universal component tester which is capable of testing most of non power electronics components.
I is capable of testing resistors, capacitors including ESR, BJTs, FETs, MOSFETs, JFETs, Thyristors (SCR, DIAC, TRIAC), IGBTs, diodes. Additionally tester is capable of measuring voltages up to 50V, frequency and even generate signals. Optionally there is an IR code detector. The tester is based on Atmega328 microcontroller which drives all testing logic and displays results on LCD screen. After building first version and seeing what needs to be improved, he plans on building second tester version which is going to be more compact and feature rich.