Most of the the rituals associated with events celebrated have their origin from non muslim cultures. someone rightly mentioned abt mayoon, mehndi & other wedding related events having their origin from hindu culture. Others include...soyem, teeja, chaliswan, barsi....all of these have no proof in hadith / quran. If u look upon books covering the life of prophet muhammad, sahaba & scholars, u wont find any links associated with such events. The prophet never celebrated basrsi of hazarat khadija or for that matter of his 2 sons who died at a very young age.
many other events are either self made or adopted from others...koonday, halwa making on shab-i-bara'at, & basant .....purely having no use & proof in islam. God has been making things easier for us & we , ourselves r adding up to our burden & keep performing them in spirit as if they ar e a must!
Pity on us!