Here are some easy ideas for introducing Spanish at home.
Montessori Materials has some free printouts in Spanish and French. It includes days of the week, months of the year, a bingo game, and much more.
Of course, there is nothing like singing Spanish songs. My kids loved singing in Spanish.
Also, introduce numbers, colors, and other subjects to your children in Spanish. Make a little Spanish Corner and do a little Spanish lesson every day. It can be very simple and done with the three period lesson. Label items in Spanish in your language corner too.
For older children, use something like the Rosetta Stone series.
Many libraries have it on their shelves.
Here is a free site to help you brush up on phrases and vocabulary-