Frequent Sky & Telescope contributor Alan Whitman (most recently author of Beyond the Familiar Veil) points out that the variable star Mira is at or near its peak brightness. Alan estimates it at magnitude 2.3, and some reports to the AAVSO place it as bright as 2.1. Either way, it's about as bright as it's been in living memory.
The name Mira means amazing or wonderful, and this star certainly qualifies. It's by far the brightest star that routinely varies by a factor of 100 or more in brightness. It's usually 9th magnitude at minimum, barely visible even with binoculars. But right now, it's one of the brightest stars in its sector of the sky.
Mira is particularly easy to locate in late 2011, since it's about 15° south of dazzling Jupiter. Hold out your right hand at arm's length with thumb and little finger outstretched. Put your thumb on Jupiter in the evening sky and tilt your hand clockwise a little; your little finger will be near Mira.
Mira is due to peak around October 1st and remain visible to the unaided eye for the rest of the year, though it should become about one magnitude fainter during each succeeding month. Keep an eye on it; you will be amazed how much the appearance of its constellation (Cetus) depends on how bright Mira is.
Mira is as extraordinary scientifically as it is to observe. It's an enormous, ancient red giant, several hundred times the Sun's diameter. Like all red giants, it's shedding mass at a furious rate. A few years ago, NASA's Galex satellite discovered that Mira's discarded gases form a comet-like tail more than 2° long that glows brightly in the far ultraviolet.
If you want to estimate Mira's brightness for yourself, use the chart below. Selected comparison stars are labeled with their magnitudes, with the decimal points omitted.