Pagans, Wiccans, do you have any rituals for releasing a negative person or situation in your life?

There are many. Do a meditation to clear your chakras and cleanse your aura. Christopher Penczak has a wonderful guided meditation that involves visualizing your aura around you and seeing any dark patches or “cords” attached to your aura. Think of what the darkness or binding is coming from (what event or person) and gently pull the cord out or clean away the dark energy. (It’s on his Inner Temple of Witchcraft CDs.)
One of my favorite (quick) things to do is visulize the negative words or energy “blowing up” as in confetti and watch them float to the ground to be re-absorbed by the Earth and turned into positive, useful energy.
To cleanse an item or space you can use holy water (spring water and sea salt blessed and infused with your intentions: cleansing and protection) or use sage and sweetgrass to smudge the item or area. Also know that the full moon can help cleanse items.
A good short ceremony to release a negative emotion, person, etc: write what is bothering you on a piece of paper. I will write it all out without re-reading it. Then I will light it and put it in my cauldron to burn itself out. Watch the smoke carry the negativity to the God/Goddess to handle the situation. When its burned out, the negativity is gone…for good.

We are in large part created by adversity. Thank them for their gift/lesson and wish them happiness.

I meditate and do grounding rituals. Sometimes I do chakra work too to help my chakras work better. It works quite well too.