Research may be part of your coursework or as as part of individual research opportunities working with professors.
See also the SEAS page on undergraduate research. Active Learning Labs also provide opportunities for students to engage in hands-on learning. We also recommend you check out the Computer Science colloquium to get a sense for what’s going on in the world of Computer Science Research.
To get to know more about faculty’s research you can take graduate or advanced undergraduate courses, look up faculty’s home pages with them, come to office hours, etc.. The following Google spreadsheet on Faculty Research Interests and Office Hours gives a useful overview of the research going on in Computer Science at Harvard. Be sure to look at the info paragraph column to get a sense of what is the background needed to get involved with each particular research group.
REU Programs (Research Experience for Undergraduates funded by NSF):