The light curves for three eclipsing binaries in the Magellanic Clouds have been obtained using CCD uVJIC photometry. One target in the LMC, MACHO*05:36:48.7−69:17:00, is an eccentric system, e = 0.20, with a period of 3.853534 ± 0.000005 d. Initial solutions indicate a primary component in the range Teff,1 = 20,000−35,000K and the secondary Teff,2 1000−2000K cooler than the primary, with inclinations ranging i = 84.2° − 86.0°. Two targets in the SMC, MOA J005018.4-723855 and MOA J005623.5−722123, have periods of 1.8399±0.0004 and 2.3199 ± 0.0003 days respectively. Both have circular orbits with the former being a semi-detached system.

Year to decade-long cyclic period changes have been observed in many classes of close binaries. The Algol binary WW Cygni shows a cyclic change in its orbital period with an amplitude of slightly more than 0.02 days and a period of 56 years. A hypothetical third or fourth body does not satisfactorily explain the observed variation in the orbital period. The change in luminosity and color of the system at primary eclipse minimum are in agreement with the model proposed by Applegate for a magnetic cycle induced period change in WW Cygni. We have commenced monitoring 9 close binaries for evidence of the luminosity and color changes consistent with the magnetic cycle hypothesis. δ Librae is suggested as a case suitable for observation with an optical interferometer to test the third body proposed for this Algol system.