Add open parti prompts to docs (#3549)

* Add open parti prompts

* More changes

docs/source/en/conceptual/evaluation.mdx

@@ -37,7 +37,8 @@ We cover Diffusion models with the following pipelines:
 
 ## Qualitative Evaluation
 
-Qualitative evaluation typically involves human assessment of generated images. Quality is measured across aspects such as compositionality, image-text alignment, and spatial relations. Common prompts provide a degree of uniformity for subjective metrics. DrawBench and PartiPrompts are prompt datasets used for qualitative benchmarking. DrawBench and PartiPrompts were introduced by [Imagen](https://imagen.research.google/) and [Parti](https://parti.research.google/) respectively. 
+Qualitative evaluation typically involves human assessment of generated images. Quality is measured across aspects such as compositionality, image-text alignment, and spatial relations. Common prompts provide a degree of uniformity for subjective metrics.
+DrawBench and PartiPrompts are prompt datasets used for qualitative benchmarking. DrawBench and PartiPrompts were introduced by [Imagen](https://imagen.research.google/) and [Parti](https://parti.research.google/) respectively. 
 
 From the [official Parti website](https://parti.research.google/): 
 
@@ -51,7 +52,13 @@ PartiPrompts has the following columns:
 - Category of the prompt (such as “Abstract”, “World Knowledge”, etc.)
 - Challenge reflecting the difficulty (such as “Basic”, “Complex”, “Writing & Symbols”, etc.)
 
-These benchmarks allow for side-by-side human evaluation of different image generation models. Let’s see how we can use `diffusers` on a couple of PartiPrompts. 
+These benchmarks allow for side-by-side human evaluation of different image generation models. 
+
+For this, the 🧨 Diffusers team has built **Open Parti Prompts**, which is a community-driven qualitative benchmark based on Parti Prompts to compare state-of-the-art open-source diffusion models:
+- [Open Parti Prompts Game](https://huggingface.co/spaces/OpenGenAI/open-parti-prompts): For 10 parti prompts, 4 generated images are shown and the user selects the image that suits the prompt best.
+- [Open Parti Prompts Leaderboard](https://huggingface.co/spaces/OpenGenAI/parti-prompts-leaderboard): The leaderboard comparing the currently best open-sourced diffusion models to each other.
+
+To manually compare images, let’s see how we can use `diffusers` on a couple of PartiPrompts. 
 
 Below we show some prompts sampled across different challenges: Basic, Complex, Linguistic Structures, Imagination, and Writing & Symbols. Here we are using PartiPrompts as a [dataset](https://huggingface.co/datasets/nateraw/parti-prompts).