From the BBC: "Maundy Thursday is the Thursday before Easter. Christians remember it as the day of the Last Supper, when Jesus washed the feet of his disciples and established the ceremony known as the Eucharist. The night of Maundy Thursday is the night on which Jesus was betrayed by Judas in the Garden of Gethsemane. The word 'maundy' comes from the command given by Christ at the Last Supper, that we should love one another."
From thisischurch.com: "In Britain it is still customary for the sovereign to give 'Maundy Money' to a number of male and female pensioners - one man and one woman for each year of the sovereign's age. The money is contained in two purses: one red and one white. The white purse contains specially minted coins - one for each year of the sovereign's life. The red purse now also contains money, in lieu of gifts which used to be offered to the poor. Up to the time of James II the sovereign also washed the feet of selected poor men."