Lent is an early Christian tradition (nowadays it's mainly Catholics, Lutherans and Anglicans who seem to follow it - be aware though, that they're the only denominations I've heard talk about it - and I only found out about Lutherans being involved in following it just then!), to prepare for Easter, and is done to remember how Jesus went away into the wilderness.
It is the 40 days between Ash Wednesday and Easter - Sundays are 'skipped' in the counting because of them being commemorating the Resurrection of Jesus Christ. This year it started on 9 Feb, and ends March 26 (Easter Saturday).
It usually involves some form of fasting - for centuries that meant meat, however now adays, it more than often means a 'limited' fast - meaning one main meal eaten each day and two snacks (making sure the two snacks do not a main meal make). Children are not supposed to fast, instead the parents are supposed to educate them on the meaning on why they fast, and what is shown by fasting.
That's about as much as I know - I've never followed it in my life (probably because my background is Pentecostal/Baptist), but my dad's side of the family know a bit about it - and I learnt a lot from my ex-stepfather's mother (she looked after a presbetry next to a rural cathedral), during the 'stations of the cross' part of the Easter service...
Sasch