A sacrament is an outward and visible sign of an inward and spiritual grace. In other words, it is something tangible that you can see, touch, taste and feel that points to something equally as real, but spiritual and intangible.
If that sounds odd, just think about what God does for us through the Incarnation of Jesus Christ our Lord!
The sacrament of Communion is a regular part of our worship and lets us participate in the reality of the sacrificial death of Christ and the family that is created through our faith in him. In the broken bread we see his broken body, in the wine we see his blood shed for us, as we share the meal together we do so in the community of faith.
The other sacrament is Baptism, which lets us experience the reality of how we are united to Christ in his death and resurrection, washed us clean and forgiven, given the gift of the Holy Spirit, and brought into the body of Christ. Check out our Baptism at New Creation? page for much more on that.