The deadline for full consideration of proposals for workshops for the 2016 program has been extended until October 30th 2015. However, proposals are accepted throughout the year and proposals for 2017 can be sent at any time as well.
You can see the activity of SPICE in 2015 at http://www.spice.uni-mainz.de/ and check out the talks of the workshops at the SPICE YouTube channel.
Applications for a SPICE workshop are encouraged if you want to organize an interdisciplinary workshop on an emergent field or where two distinct fields or sub-areas are brought together to explore new directions.
Also, although a spin-related area is encouraged, its connection does not have to be direct. Spin is linked directly or indirectly to a very broad area solid state physics and materials science. Hence, besides typical spintronics fields, most areas of condensed matter physics are being considered as potential workshop topics as well.
Find all the information here.