ACT institutions offer summer research opportunities for undergraduate students, including:

Princeton PSURE and USURP Programs

https://gradschool.princeton.edu/diversity/princeton-summer-undergraduate-research-experience
http://www.princeton.edu/astro/undergraduate/usrp/

Cornell LSAMP and Community College Student Programs

http://www.engineering.cornell.edu/diversity/summer/lsamp.cfm
http://www.lepp.cornell.edu/StudentOpportunities/SrccsProgram.html 

U. Penn & Philadelphia LSAMP program

http://www.philadelphiaamp.org/index.html#

U. Michigan LSAMP program

http://milsamp.engin.umich.edu/

Haverford Chesick Scholars

http://www.haverford.edu/chesick/

Stony Brook URECA program

http://www.stonybrook.edu/commcms/ureca/summer/urecasummer.html

Rutgers REU program

http://reu.physics.rutgers.edu/

Toronto SURP program

http://dunlap.utoronto.ca/education/surp/

ACT recently did an evaluation of its summer research program and the results were quite positive. We are confident that the undergraduates working summer projects with ACT collaborators have had great experiences. A full report of the evaluation can be found here.