Sight reading is one of those things that is an indispensable skill for musicians. If you want to be part of an orchestra, chamber group, vocal group or any kind of group of musicians, the ability to sight read makes the experience so much more enjoyable, less stressful and fun.
Today I discovered a website which gives you the opportunity to practise! The free version concentrates on rhythm, and you can sign up for a free one month trial with memory added to your rhythm. You can create your own rhythm by choosing the meter (duple, triple, compound, odd such as 5/8, 7/8 etc), number of bars (measures) and degree of difficulty (between 1 and 5). The rhythm is then played back to you while you clap along. The settings for playback include the ability to change the instrument (eg piano, clarinet, flute, guitar, drums, violin etc), the tempo, and format.
Below is a screen shot (click to see full size). Check the website out here!