A sacrament is when something holy happens. It is transparent time, time which you can see through to something deep inside time.
Generally speaking, Protestants have two official sacraments (the Lord’s supper, Baptism) and Roman Catholics these two plus five others (Confirmation, Penance, Extreme Unction, Ordination, and Matrimony). In other words, at such milestone moments as seeing a baby baptized or being baptized yourself, confessing your sins, getting married, dying, you are apt to catch a glimpse of the almost unbearable preciousness and mystery of life.
Needless to say, church isn’t the only place where the holy happens. Sacramental moments can occur at any moment, any place, and to anybody. Watching something get born. Making love. A high-school graduation. Somebody coming to see you when you’re sick. A meal with people you love. Looking into a stranger’s eyes and finding out he’s not a stranger.
If we weren’t blind as bats, we might see that life itself is sacramental.