Plunteria

Today is Athena's festival on the Attic calendar. What would be a good offering to give Her?

The Πλυντήρια was a public-sphere festival in Athens, specifically, rather than a private observance.

Actually, it marked the time when the special garments that were used to clothe the Acropolis' statue were ceremonially washed (if my memory serves me right, in the sea).

Any typical veneration of Pallas would be appropriate. If you have an image of the deity, it would be appropriate to offer or dress the image in saffron-colored cloth (that was what was used to dress the image on the Acropolis), however, nothing that elaborate is necessary. As I mentioned, it was a public festival focused on a particular statue and shrine in Athens, not really a private observance.

Hope that helps.

Erodius wrote:If you have an image of the deity, it would be appropriate to offer or dress the image in saffron-colored cloth (that was what was used to dress the image on the Acropolis), however, nothing that elaborate is necessary.

On the topic of dressing images, this thread on another forum is interesting.
http://www.religiousforums.com/forum/hinduism-dir/163076-deity-clothing.html
The pictures start appearing on page 3.

Indeed – the practice is called vastra in Sanskrit.

It is a typical element of most formal Hindu temple ceremonies – though less so in private cultus, where the large images that are clothed in vastra rituals are often beyond the means or facilities of a private household. Though, particularly in Krishnaite Vaishnavism, home-scale smaller images of Krishna and Radha are used in worship, which are sold with sets of tailored vastra garments specially for the images.

Sometimes, however, a small-scale nod to the vastra ceremony is performed wherein smaller images, or even framed icons, have a strip of sacred cloth tied around them or draped over the frame.