Khrystos Voskres! (Christ is Risen)! Voistyno Voskres! (Indeed He is Risen!)
It's Easter (Velekden - The Great Day) for those Christians following the Gregorian calendar!
This would, of course, include various Protestant denominations as well as Western (Roman) Rite Catholics, and many Eastern Rite Catholics.
The remaining Ukrainian Catholics who follow the Julian calendar for religious holidays will celebrate Easter next Sunday with their Ukrainian Orthodox brethren and sistren.
This somewhat confusing calendar situation is actually quite beneficial. It allows for two opportunities to celebrate major holidays, so a person can either do it twice or celebrate on the calendar date that best suits one's particular life situation. This is very convenient for families of mixed heritage as well as shift-workers. :-)
For a lovely overview of Ukrainian Easter traditions (and a couple of recipes) check out the UkeMonde site (here). It includes a rundown of the contents of the traditional Easter basket that is taken to church for blessing. This information can also be heard on Nash Holos tonight, along with traditional Easter music. (If you aren't able to tune in, no worries! The program will be archived and available as a podcast.)
In the meantime, I'd like to share with you this charming video about pysanky - how they're made and the symbolism of the designs (both Christian and pre-Christian):