If you don't have plans yet, chances are many of your friends don't either, so if you invite people over even with little notice, they'll most likely attend. Many people feel overwhelmed by the pressure to go out and have a blast, but the traffic and jacked up prices at restaurants can deter people from wanting to go out.
Thin leather is the hottest trend for Spring. It can also just appear to have a leather quality/sheen. Typically thought of as a Fall/Winter material, pairing the thin leather with softer more vintage jewelry or lace also adds a more Spring element to it. Cut outs on the neck or hem also make the leather dress cool and chic.