There is no lack of assessment tools, if you use your imagination. One of the most effective way to capture pre-assessment in a low-tech, or no-tech way is to have students begin your lesson with a "graffitti placemat." I used to call these graffitti walls and this can be done in a group with bulletin board paper, but a better artifact, down at the student level, would be to use this as a "placemat." (Thanks to Karin in Fort Ann for adding this new twist.) With an 11 x 14 piece of paper, each student can name & date that placemat.
In theory, at the beginning of a lesson the placemat might be weak, anemic, sparse, or blank. Hopefully after your instruction, in a different color pen or pencil, the student will be able to answer the same question with a deeper level of understanding. Thus you have your assessment artifact-- name and date.
This can be replicated via Mind Mapping software also. Mindmeister.net is a wonderful tool that can be used to mind map knowledge and visibly show student growth. However, technology like this has a big learning curve, and you might now want to eat up your instructional time teaching "mapping software."
That is when it might be advantageous to use the 'ole pencil and paper trick. Hit your Staples Easy button... a very successful, visible way to pre and post assess your instruction.
* Another web 2.0 tool you could use for assessment could be Doodle.com Most people think of this site as a "scheduler." However, with innovative creative thought, you can create multiple choice questions that would archive student knowledge. Next time you log into Doodle.com, you might want to choose "make a choice" rather than "schedule".
Just think "content" rather than "food." How's that for food for thought?