Calculate your biorhythms. It computes your 23-day physical, 28-day emotional, 33-day intellectual and combined cycles. The combined cycle is sometimes called the luck cycle. The theory of biorhythms is when the cycles are positive/high you will have high energy. When they are negative/low you will have low energy. When they are zero or critical, you will have unstable energy. The Biorhythm Calculator is also available with Java source to download.
Requires Java 1.1+