The April edition of the Journal of Chemical Education has an interesting experiment that introduces students to the fabrication of a microfluidic device. The device uses a simple Y-channel design. After fabricating the device, students can use it to explore laminar flow at the interface of fluids merging at the interface between the two channels, to observe an acid-base reaction at the interface, and to observe the precipitation of CaCO3 crystals at the interface.
The full citation is here: Chia, M. C.; Sweeny, C. M.; Odom, T. W. J. Chem. Educ. 2011, 88, 461–464 and a link to the article is provided below (subscription to the journal required).