Basic setup: One student is selected to be Pedro Pistolas, the champion and is placed at the front of a line. The next student is the first challenger. The line rotates as students proceed through the vocabulary.
A term from their vocabulary is prompted (by a picture, where possible) and the first student to respond either becomes or remains the champion. The line should be gone through at least a couple of times so that every student has multiple opportunities to succeed.
Optional rule: If the class has vastly different levels of students, a limit can be placed on consecutive victories before that champion moves to the back of the line.
Another optional rule: Students with sufficient knowledge to do so may be prompted to form sentences using the words after correctly naming the item in question. This allows the activity to be somewhat more communicative as the students are presented an open-ended opportunity to express themselves.