if you really want some kick @$$ mentalism, check out Kenton Kneppers stuff. Here's the stuff included in banacheck's Pre Thoughts :
1. Be Seated!
An envelope is handed to an audience member. Three audience members each select a seat from a row of four chairs, so that one chair is empty. The audience member holding the envelope opens it to reveal the performer's correct prediction as to which chair would be left empty.
2. A Cheap Add A Number!
The performer hands a stack of index cards to three audience members, each of which writes down a three-digit number. A fourth audience member totals them and memorizes. The performer again shows the numbers to the other participants to verify the honesty of the proceedings. The fourth audience member writes the total on a large whiteboard or blackboard, the other half of which is covered with newspaper. The performer whips the newspaper away, revealing that the prediction beneath it is a perfect match.
3. The Alphabet Game!
An audience member is asked to stand and name any letter of the alphabet (he can change his mind if he wishes). The performer explains the psychology of his choice while removing a business card case from his pocket. He extends the case to the audience member and has him remove the business card inside. On its back is written the correct letter.
4. Future Card Thought!
The performer has an envelope held by an audience member. Another audience member shuffles a deck, which is boxed but not closed to enable cards to be dealt without any possibility of sleight of hand. The audience member deals a five-card hand of poker from it and pockets the deck as a souvenir. He then concentrates on one of the cards. The performer names it, and successfully names each of the cards thought of until one card is left. The performer asks the audience member to name the remaining card. When the envelope is opened, it contains a duplicate of this card.