Probably the most profound part of the liturgical year. The Church pulls out some of her richest traditions and symbolism at this time. Foot washings, candles, light and darkness, processions, incense...all of it. And of course, these are all there to help us renew our appreciation of that which is even more profound: the Sacraments, and from whom they come.
Today is Holy Thursday. The last day on which Mass is celebrated between now and Easter. The Blessed Sacrament is removed from the main tabernacle in the church, and placed in a temporary location, reminding us of the three days in the tomb.
Tomorrow is Good Friday, on which we remember the Crucifixion. Don't forget to fast and pray! After you to your Good Friday services at your parish, this is a good time to pull out those "Passion of the Christ" DVD's.
Beginning late Saturday night we await the resurrection, and the beginning of Easter Sunday at Easter Vigil. The Easter Vigil is the biggest party we Catholics have all year. (Easter is a big deal among other Christians, too, but Catholics and Orthodox Christians take it to a whole other level, liturgically speaking) If you think Midnight Mass at Christmas is amazing, you should see Easter Vigil at least once. If you can't make it, there's always a daytime mass on Easter Sunday.
And it doesn't stop there. We keep the Easter celebration going for an entire season, and of course we continue to celebrate it all year at every mass. After all, ladies and gentlemen, "God so loved the world that he gave his only Son, so that everyone who believes in him might not perish but might have eternal life". It doesn't get any more worth celebrating than that.