[Your Name, & Address here]
[Recipient Name & address here]
It has been a long time since we met last. Both of us are so busy nowadays that we do not get time to have fun together.
If you have free time on the coming [day or date], let’s – [state here activity you plan to do]. If you have any better idea, please tell me about it.
Call me or send me a message to know if are free. I can’t wait for your response.