  We present an updated catalog of 4680 northern eclipsing binaries (EBs) with
Algol-type light curve morphology (i.e., with well-defined beginning and end of
primary and secondary eclipses), using data from the Catalina Sky Surveys. Our
work includes revised period determinations, phenomenological parameters of the
light curves, and system morphology classification based on machine learning
techniques. While most of the new periods are in excellent agreement with those
provided in the original Catalina catalogs, improved values are now available
for ~10% of the stars. A total of 3456 EBs were classified as detached and 449
as semi-detached, while 145 cannot be classified unambiguously into either
subtype. The majority of the SD systems seems to be comprised of short-period
Algols. By applying color criteria, we searched for K- and M-type dwarfs in
these data, and present a subsample of 609 EB candidates for further
investigation. We report 119 EBs (2.5% of the total sample) that show maximum
quadrature light variations over long timescales, with periods bracketing the
range 4.5-18 yrs and fractional luminosity variance of 0.04-0.13. We discuss
possible causes for this, making use of models of variable starspot activity in
our interpretation of the results.
