It's the time of the year again, so I'd be interested hear what new (and old) ideas have come up. Previously asked on:
2024 → https://news.ycombinator.com/item?id=42373343
2023 → https://news.ycombinator.com/item?id=38467691
2022 → https://news.ycombinator.com/item?id=34190421
2021 → https://news.ycombinator.com/item?id=29667095
2020 → https://news.ycombinator.com/item?id=24947167
2019 → https://news.ycombinator.com/item?id=20899863
2018 → https://news.ycombinator.com/item?id=17790306
2017 → https://news.ycombinator.com/item?id=15148804