Is human life inherently meaningless? Do we have a purpose? Basically, we are the culmination of billions of years of dust floating around in space, collecting together, gravitating enough to start fusing and sending energy to other little bits nearby. That energy was used in chemical reactions that, after another obscene amount of years, are now able to consciously alter, maintain, or even end their existence. Arguably, we even intimately connect with every other particle in the universe via quantum entanglement. We don't just exist in the universe; we ARE the universe. I find that incredibly remarkable, and I see as having purpose for being here, right now.
If this is the only life we have to live, if it is the only chance we get to touch people's lives and enrich our own, then I consider living it. We can live for pleasure, or we can live a life in which we both grow on a personal level, and touch the lives of others in some meaningful way. It's an oversimplification, but it's probably the most meaning you can expect to find in a godless universe. There is no objective meaning of life, or purpose, but we create our own meaning, both as a society and an individual. For me, it's the acquisition of knowledge, the pursuit of truth, perfection, of human unity. Life fascinates me, and as suffering as it can be and has been, curiosity keeps me here.