In one book, they simply shouted out words.
And of course the rubbing of the lamp.
There are others, but I have to go. Bus. Crud.
Have a nice morning.
Oh, and I think Eragon did it differently, I should check again.
Ha, my sister is late so we get driven to school.
Ok, right naming some more now:
There has also been the case where they use an altar/special clothes/ect. to attract the spitit.
Note: These aren't all fantasy books, I've come across them in books about people's culture.
"You belong in Gryffindor,
where dwell the brave at heart,
Their daring, nerve and chivalry
set Gryffindors apart."