Formal:
* ତୁମେ କ'ଣ କରୁଛ ତୁମେ? (Tume ka'na karuchhi tume?) - This is the most literal and formal way to say it.
Informal:
* ତୁମେ କ'ଣ କରୁଛ? (Tume ka'na karuchhi?) - This is a more casual and commonly used phrase.
Even more informal:
* କ'ଣ କରୁଛ? (Ka'na karuchhi?) - This is a very informal way to ask, used with friends or family.
Using verbs:
* ତୁମେ କ'ଣ କରୁଛ (Tume ka'na karuchhi) ଏବେ? (ebe?) - This translates to "What are you doing now?"
* ତୁମେ କ'ଣ କରିବାକୁ ଯାଉଛ? (Tume ka'na karibaaku jaauchhi?) - This translates to "What are you going to do?"
Remember that the best way to choose the right phrase is to consider the context and your relationship with the person you are talking to.